Episulfide compounds are used in a wide variety of fields such as raw material compounds for plastics, adhesives, medicaments, insecticides, and herbicides.
Particularly, in recent years, plastics formed by polymerizing episulfide compounds have characteristics such as a high refractive index, a high Abbe number, high heat resistance and high strength. Therefore, those plastics have been traditionally used as materials having excellent performance in the field of optical materials.
In general, an example of the method for producing an episulfide compound is a method of allowing an epoxy compound to react with a thiating agent.
However, when an episulfide compound is produced by this method, there has been a problem that since there occurs the formation of a polymerization product caused by the high reactivity of the episulfide compound, and a reaction between the episulfide compound and the thiating agent, it is difficult to obtain the episulfide compound with a high yield. Furthermore, since the reaction between an epoxy compound and a thiating agent is slow, the reaction time is long, and there has been a demand for an improvement in terms of productivity.
In order to solve these problems, several methods have been suggested. For example, Non-Patent Literature 1 suggests a method of using a novel thiating agent. Non-Patent Literature 2 suggests a method of using a metal catalyst. Non-Patent Literature 3 suggests a method of using an acid catalyst supported on silica. Patent Literature 1 suggests a method of using only a polar solvent as a reaction solvent.